Re: [patch] add kdump_after_notifier

Takenori Nagano
2007-08-16T09:27:50Z

Vivek Goyal wrote:
> So for the time being I think we can put RAS tools on die notifier list
> and if it runs into issues we can always think of creating a separate list.
>
> Few things come to mind.
>
> - Why there is a separate panic_notifier_list? Can't it be merged with
> die_chain? die_val already got one of the event type as PANIC. If there
> are no specific reasons then we should merge the two lists. Registering
> RAS tools on a single list is easier.

I think it is difficult, because die_chain is defined by each architecture.

> - Modify Kdump to register on die_chain list.
> - Modify Kdb to register on die_chain list.
> - Export all the registered members of die_chain through sysfs along with
> their priorities. Priorities should be modifiable. Most likely one
> shall have to introduce additional field in struct notifier_block. This
> field will be a string as an identifier of the user registerd. e.g
> "Kdump", "Kdb" etc.
>
> Now user will be able to view all the die_chain users through sysfs and
> be able to modify the order in which these should run by modifying their
> priority. Hence all the RAS tools can co-exist.

This is my image of your proposal.

- Print current order

# cat /sys/class/misc/debug/panic_notifier_list
priority name
1 IPMI
2 watchdog
3 Kdb
4 Kdump

- change list order

# echo <before> <after> > /sys/class/debug/panic_notifier_list

- example

# cat /sys/class/misc/debug/panic_notifier_list
priority name
1 IPMI
2 watchdog
3 Kdb
4 Kdump

# echo 4 1 > /sys/class/debug/panic_notifier_list
priority name
1 Kdump
2 IPMI
3 watchdog
4 Kdb

Is my image almost same as your thought?

Thanks